Various forms of portable brick making apparatus have been devised for achieving the high volume production of pressed earth bricks near a proposed building site. These generally employ "earth" material which is provided at the site and is hydraulically compressed into a mold to form a brick. The apparatuses are designed to produce a brick of one size and are not easily convertible to the manufacture of different sized bricks, such as wall or truss bricks or specialty bricks which could be used as floor tiles or roof tiles for the structures to be built therefrom or for decorative purposes, without stopping the machine to change the molds. U.S. Pat. Nos. 3,225,409 and 4,557,681 disclose adobe brick making apparatus for making a given sized brick but which is difficult to adapt to manufacture bricks of a different size without a major and time consuming changing of their mold components which must be done with the machines production stopped long enough to make the changes.